Double up?

[Billthebuilder]

Is it advised to use two washers when bolting the heads down ? It seems the new steel studs are a tad longer and I would like to have more to bite on. 2.7 build

['76 911S 3.0]

Did you set the stud height when installing them? When set properly, you only need one washer.

[Walt Fricke]

135mm is the installed height here for the studs.

I think guys should always throw away those barrel nuts that take a hex. Use a flange nut with the right thread. Those take one socket smaller size than a regular nut of the same thread size, and the socket will fit down the hole in the fins.

That way you never end up with the stud top pushing the Allen out of the socket before you get the torque you are aiming for. And you don't find that you have rounded off the very tip top of the hex and can't back the barrel nut off if you want to remove it.

Is the nut in the photo torqued?

[Tom '74 911]

Originally Posted by Walt Fricke

I think guys should always throw away those barrel nuts that take a hex. Use a flange nut with the right thread. Those take one socket smaller size than a regular nut of the same thread size, and the socket will fit down the hole in the fins.

Walt,

I think that's a great tip... do you use flange nuts w/flat or serrated bottoms as replacements?

Tom

[Tippy]

Originally Posted by Tom '74 911

Walt,

I think that's a great tip... do you use flange nuts w/flat or serrated bottoms as replacements?

Tom

You'd need flat. The serrated would effect torque. Not a good thing when doing torque, then degree.

[Tippy]

Originally Posted by Walt Fricke

I think guys should always throw away those barrel nuts that take a hex. Use a flange nut with the right thread. Those take one socket smaller size than a regular nut of the same thread size, and the socket will fit down the hole in the fins.

That way you never end up with the stud top pushing the Allen out of the socket before you get the torque you are aiming for. And you don't find that you have rounded off the very tip top of the hex and can't back the barrel nut off if you want to remove it.

You know, that is a great idea. I may do that too.

[Flat6pac]

If you look, I found the flange nuts with 15 mm shoulders, a lot easier with smaller socket.
Bruce

[KTL]

$6 for 24 of the zinc plated class 10 nuts from Belmetric. Or you can get a bag of 50 nuts from McMaster for $9

https://www.belmetric.com/flat-bottom-flange-nut-c-3_48_1592_59_1294/nffh10ylw-flange-nut-smooth-yellow-zinc-cl10-p-7760.html?zenid=h4e75mrrbt6fo8p1k86eesade2

[Billthebuilder]

I did measure the height but the book says 135 to 137 is within spec Ollies did my case. Still I had a difficult time getting the height under 137 rather than fight it I'll change the nuts! Thanks for all the help I'll post up when I get there

[Walt Fricke]

I hadn't considered whether to use serrated base flange nuts or flat base ones. I know the ones I bought to use on a couple of engines are flat base - I looked in my stock of spares.

But Henry Schmidt supplies serrated base ones with his Supertec studs - I looked at some of those awaiting rebuilding of another of my motors. Those are the studs with a fine rather than a coarse thread at the cylinder head end. Henry seldom does something just by accident, so he may have examined this question and reached a reasoned conclusion. Plus he's sold a lot of these stud kits, and if serrated bases were a problem in this application, he'd have learned about it.

I'd not think that the serration would help prevent the nut from backing off - the thick washer is hardened steel too. If the serrations resist being tightened, I agree you might end up with less than the torque you thought you had if you just use a wrench. Though on the other hand if the serrations actually grab when being tightened, the washer could still move and you might get the stretch you want. Stretch is the goal here, but it is hard (impossible?)to measure compared with rod bolts.

Then again, if the serrations collapse a bit under the tension imposed, I can see how that might affect the torque plus degrees approach Porsche recommends.

But I put this into the category of something I'm not going to worry about. I've never had either type get loose, nor had a head to cylinder seal fail due to lack of clamping force.

[cgarr]

Just something interesting:

[Billthebuilder]

Those nord locks look amazing 10 mm pre gluded halfs a package of 6 - 24.99